The objective of this invention is to provide a simplified, compact and operationally convenient selector valve having a universally pivoted joy stick control handle whereby an operator can deliver motive fluid selectively to remove devices for individual operation or operation in pairs. While the invention has the capability of wide utility, it is ideally suited for controlling the operation of outrigger jack cylinders on construction cranes and similar equipment. Such cranes may have four outrigger arms, two on each side of the crane, and each equipped with a ground-engaging jack or leg which is extended and retracted at proper times under control of a hydraulic cylinder. In such an application, the present invention will embody in a single selector valve assembly four two-way spool valves which are biased to a closed position and are easily shifted, one at a time or in selected pairs, to an open position by the use of a joy stick having a ball swivel connection with the valve casing and carrying a conical disc which cammingly engages extensions of the individual valve spools exteriorly of their casings to drive them toward their open positions.
The construction of the selector valve allows the use of only one low pressure fluid seal on each valve spool, and provision is made in the valve for draining all of the spool valve bores through a common drain passage and port at one end of the assembly and for venting the valve spool. Another unique feature of the device tending to make it foolproof and damage-proof during operation is an arrangement whereby the cover or mounting plate at one end of the valve casing forms a positive stop surface for the peripheral portion of the conical disc carried by the joy stick operator or lever. This arrangement limits the swing of the joy stick in all directions.
Other features and advantages of the invention will become apparent to those skilled in the art during the course of the following description.